Developing effective tobacco cessation interventions during pregnancy for American Indian and Alaska Native people is a national priority and will contribute to the U.S. public health objective of reducing tobacco- related health disparities. In the southwest region of Alaska where the proposed project will take place, 79% of Alaska Native women smoke cigarettes or use smokeless tobacco (ST) during pregnancy. In addition, pregnancy appears to be a high risk period for initiation of tobacco use, primarily ST, among women reporting no use of tobacco 3 months before pregnancy. Our pilot study suggested that an individual-based intervention delivered at the first prenatal visit had low reach to pregnant women and poor tobacco abstinence rates. Intervention efforts targeting the entire community, not only pregnant women, to address social norms about tobacco use may be more effective. Thus, we propose to evaluate the efficacy of a novel, multi-component, theory-based intervention for reducing tobacco use during pregnancy, incorporating both individually targeted and community level components delivered by female elders Native Sisters. The intervention builds on effective community and individual-based approaches for tobacco cessation and lay health advisor approaches for cancer prevention among Native American women. As part of the intervention, a social marketing campaign including digital stories and other small media will be developed with community feedback. Individually targeted components will be six 30-40 minute telephone or home-based peer counseling sessions with pregnant women. This R01 project is submitted in response to PAR-11-346. It will be conducted in two phases. All aspects of the project will be guided by a community advisory committee. In Phase I, we will develop the social marketing components by obtaining qualitative feedback from pregnant women, family members and elders on message content and delivery channels. In Phase II, we will evaluate the intervention using a group- randomized design with village as the unit of assignment. Sixteen villages will be randomly assigned to receive the intervention or control condition (usual care), with > 20 women enrolled from each village. Enrollment will occur at the time of a positive pregnancy test which is the earliest point of prenatal care, enhancing the intervention's potential reach. Both tobacco users and non-users will be eligible because many start to use during pregnancy. Assessments will be completed by enrolled women through 6 months postpartum. We will evaluate the efficacy of the intervention compared with the control condition on the biochemically confirmed 7-day point prevalence tobacco use rate at week 36 gestation and at 6 months postpartum. We will also examine the effect of the intervention on proposed social cognitive-theory based mediators of change including perceived self-efficacy for non-tobacco use and anti-tobacco norms. Our long term objective is to determine effective interventions for Alaska Native women that will ultimately reduce the risk of tobacco-related maternal, fetal, and infant adverse health outcomes.